1. Field of the Invention
The invention relates to a lens device, more particularly to a retractable lens device.
2. Description of the Related Art
Taiwanese Patent Publication No. I 229231 discloses a conventional lens device adapted for use with a camera (not shown). FIGS. 1, 2 and 3 illustrate some elements of the conventional lens device 1 disclosed therein.
The conventional lens device 1 comprises a base plate 11, a cam post 12 extending from the base plate 11 and formed with an inclined cam surface 121, a first lens module 13, a second lens module 14, and a lens barrel 15. The first lens module 13 is mounted pivotally on the lens barrel 15, is surrounded by the lens barrel 15, and has a first lens unit 130, a pivot portion 131, a guide block 132 abutting against the cam surface 121, and a torsion spring 133.
When the camera is turned off, the lens barrel 15 is driven to move toward the base plate 11 along an optical axis (Z1), and the first lens module 13 pivots about the pivot portion 131 while the guide block 132 slides on the cam surface 121, such that the first lens module 13 rotates to a retreating position (not shown) where the first lens unit 130 is not disposed on the optical axis (Z1), and the torsion spring 133 accumulates a restoring force. On the contrary, when the camera is turned on, the lens barrel 15 is driven to move away from the base plate 11, and the restoring force of the torsion spring 133 biases the first lens module 13 to rotate to a shooting position (see FIG. 3) where the first lens unit 130 is disposed on the optical axis (Z1). The movement of the first lens module 13 makes room for the lens barrel 15 to move as close as possible to the base plate 11 along the optical axis (Z1), thereby retracting the conventional lens device 1 when the camera is turned off.
However, since the second lens module 14 is secured on the base plate 11, it can not move to make extra room for further retracting of the conventional lens device 1.